The centerpiece of this proposal is the new found, extraordinary lipooligosaccharide antigens, ubiquitous among atypical (nontuberculous) mycobacteria and perhaps present in Mycobacterium tuberculosis and Mycobacterium leprae. Those from Mycobacterium kansasii are characterized by a glycosidic trehalose-containing "core", modulated by species-specific sugars and acyl substituents. State-of-the-art chemical analysis (e.g. 360 MHz 1H- and 13C-NMR; gas liquid chromatography/mass spectrometry; fast atom bombardment/mass spectrometry) will be applied, probing the variety of trehalose-containing "cores" and the relationship of species-specific sugars and acyl functions to the "cores". Analysis of the pyruvic acid-containing "C-mycoside" glycopeptidolipid (GPL) antigens of the Mycobacterium avium/Mycobacterium intracellulare/Mycobacterium scrofulaceum complex will continue in concert with a probing of their biosynthesis, based on observations that they originate in water-soluble glycopeptides and are susceptible to D cycloserine. The role of lysogenic conversion in the multiplicity of glycopeptidolipid-containing serotypes in nature will be explored. In addition, the clinical application of the species-specific glycolipids, incorporated into enzyme linked immunosorbent assays, in identification of pathogens and direct serodiagnosis of disease will continue. The physiological function and role in pathogenesis/persistence of the species-specific lipooligosaccharides/glycopeptidolipids will be explored with emphasis on the theorm of an inert lipoidal capsule.